Electroplating tool and method for selective plating

Abstract

A tool for electroplating a portion of the surface of each of a plurality of pieces includes a first plate having a plurality of holes, and a second plate having a plurality of retaining elements. Each of the holes is configured to receive a piece that is to be electroplated, and to mask a portion of the surface and expose another portion of the surface of the piece. The first and second plates are held together, and a mechanism is provided for shifting one of the plates with respect to the other between a first orientation in which the retaining elements are disengaged from pieces received in the holes and a second orientation in which the retaining elements are engaged with pieces received in the holes. This arrangement allows the pieces to be quickly and easily retained for an electroplating operation and released after the electroplating operation.

1. An electroplating tool for selectively plating a portion of the surface of each of a plurality of pieces, comprising:
 a first plate having a face defining a plurality of holes arranged in a pattern, each of the holes configured to receive a piece that is to be electroplated, each hole further being configured to mask a portion of the surface of a piece received in a hole and expose another portion of the surface of the piece for electroplating; 
 a second plate having a plurality of retaining elements, the second plate being held in a predetermined spatial relationship with respect to the first plate; 
 a mechanism for shifting one of the first and second plates with respect to the other of the first and second plates between a first orientation in which the retaining elements are in a position corresponding to disengagement with pieces received in the holes and a second orientation in which the retaining elements are in a position corresponding to engagement with pieces received in the holes; and 
 a means for applying electrical current to cause electroplating on the surface of each piece that is exposed for electroplating. 
 
     
     
       2. The electroplating tool of  claim 1 , wherein the retaining elements are prongs that project from a face of the second plate, the prongs arranged on the second plate in a pattern corresponding with the pattern of holes in the first plate, whereby each of the prongs can be inserted through a corresponding hole in the first plate and through an opening in a piece that can be located in the hole. 
     
     
       3. The electroplating tool of  claim 1 , wherein the second plate is held in the predetermined spatial relationship with respect to the first plate by a frame carrying the mechanism for shifting one of the plates with respect to the other. 
     
     
       4. The electroplating tool of  claim 3 , wherein the mechanism for shifting one of the first and second plates with respect to the other of the first and second plates comprises threaded bores extending through one of the first and second plates and screws received in the threaded bores, said screws extending through said frame, whereby shifting of said first plate with respect to said second plate is achieved by rotation of said screws. 
     
     
       5. The electroplating tool of  claim 1 , wherein the mechanism for shifting one of the first and second plates with respect to the other of the first and second plates between said first orientation and said second orientation is configured to further allow shifting between said first orientation and a third orientation in which the retaining elements are in a position corresponding to engagement with pieces received in the holes, movement from the first position to the third position being in a direction opposite of movement from the first position to the second position, whereby the direction of forces applied to the retaining elements may be reversed for alternating electroplating processes so that permanent deformation of the retaining elements can be prevented. 
     
     
       6. The electroplating tool of  claim 1 , wherein the mechanism for shifting one of the first and second plates with respect to the other of the first and second plates includes at least one stop to limit the distance that the first and second plates can be shifted with respect to one another, whereby permanent deformation of the retaining elements can be prevented. 
     
     
       7. The electroplating tool of  claim 1 , wherein the first plate includes a plurality of electrically conductive posts that can be electrically connected to an electroplating circuit, whereby at least one electrical conductor can be extended between at least two of the posts to allow electrical current to be drawn away from certain surfaces of certain pieces to achieve more uniform plating of all surfaces of all pieces than would be possible without the posts and electrical conductor connected to the electroplating circuit. 
     
     
       8. The electroplating tool of  claim 1 , wherein notches are defined in the frame for engaging support rods which allow the tool to be easily suspended in an electroplating solution or at the surface of an electroplating solution, with surfaces of pieces to be electroplated in contact with the electroplating solution, and with at least a portion of the tool being suspended above the electroplating solution to reduce undesirable plating of the tool. 
     
     
       9. The electroplating tool of  claim 1 , wherein the first plate is electrically conductive and can be electrically connected to an electroplating circuit. 
     
     
       10. The electroplating tool of  claim 9 , wherein an electrically insulative material is located on selected surfaces of the first plate to reduce electrical current at certain surfaces of certain pieces to achieve more uniform electroplating thicknesses of all surfaces of all pieces than would occur without the insulative material located on the selected surfaces of the first plate. 
     
     
       11. The electroplating tool of  claim 1 , wherein the first plate is electrically insulative, and the retaining elements are electrically conductive and electrically connected to an electroplating circuit. 
     
     
       12. The electroplating tool of  claim 1 , wherein each of the holes includes a tapered section defining a shoulder that serves as a stop for the pieces and establishes the amount of surface of the piece that is exposed for electroplating. 
     
     
       13. The electroplating tool of  claim 1 , wherein each of the holes has a uniform diameter through the thickness of the first plate, and the first and second plates are held in abutment so that the second plate acts as a stop for the pieces and together with the thickness of the first plate establish the amount of surface of the piece that is exposed for electroplating. 
     
     
       14. A process for selectively electroplating a surface of each of a plurality of pieces, comprising:
 providing an electroplating tool having a first plate including a face defining a plurality of holes arranged in a pattern, each of the holes configured to receive a piece that is to be electroplated, each hole further being configured to mask a portion of the surface of a piece received in the hole and expose another portion of the surface of the piece for electroplating, a second plate having a plurality of retaining elements, and a frame holding the first plate and the second plate in a predetermined spatial relationship, the frame including a mechanism for shifting one of the first and second plates with respect to the other of the first and second plates between a first orientation in which the retaining elements are in a position corresponding to disengagement with pieces received in the holes and a second orientation in which the retaining elements are in a first position corresponding to engagement with pieces received in the holes; 
 locating a piece that is to electroplated on a selected portion of its surface in each of the holes; 
 shifting one of the first and second plates with respect to the other from the first orientation to the second orientation to retain the pieces in the holes; 
 positioning the plating tool retaining the pieces so that at least the portion of each piece that is to be plated and which is received in one of the holes is immersed in an electroplating solution; and 
 applying an electrical current through the electroplating solution while at least the surface of each piece that is to be electroplated is immersed in the electroplating solution to cause electroplating on the surface of each piece that is exposed for electroplating. 
 
     
     
       15. The process of  claim 14 , wherein the first plate includes a plurality of electrically conductive posts that can be electrically connected to an electroplating circuit, whereby at least one electrical conductor can be extended between at least two of the posts to allow electrical current to be drawn away from certain surfaces of certain pieces to achieve more uniform plating of all surfaces of all pieces than would be possible without the posts and electrical conductor connected to the electroplating circuit. 
     
     
       16. The process of  claim 14 , wherein the first plate is electrically conductive and is electrically connected to an electroplating circuit, and wherein an electrically insulative material is located on selected surfaces of the first plate to reduce electrical current at certain surfaces of certain pieces to achieve more uniform electroplating thicknesses of all surfaces of all pieces than would occur without the insulative material located on the selected surfaces of the first plate. 
     
     
       17. The process of  claim 14 , in which the entire tool holding the pieces for electroplating is immersed in the electroplating solution during application of the electrical current. 
     
     
       18. The process of  claim 14 , in which the tool is suspended so that surfaces of the pieces that are to be electroplated are immersed in the electroplating solution and at least a portion of the tool is above the electroplating solution during the electroplating process to reduce undesirable plating of the tool. 
     
     
       19. The process of  claim 14 , wherein the retaining elements are prongs that project from a face of the second plate, the prongs arranged on the second plate in a pattern corresponding with the pattern of holes in the first plate, whereby each of the prongs is inserted through a corresponding hole in the first plate and through an opening in a piece that can be located in the hole. 
     
     
       20. The process of  claim 14 , in which the tool is mounted on a frame and totally immersed in the electroplating solution for electroplating the pieces.